Fluoroelastomers

ABSTRACT

Fluoroelastomers comprising in the polymer chain units deriving from fluorovinyl ethers having the formula:  
     CFX═CXOCF 2 OR  (I)  
     wherein R is a C 2 -C 6  linear, branched or C 5 -C 6  cyclic (per) fluoroalkyl group, or a C 2 -C 6  linear, branched (per) fluorooxyalkyl group containing from one to three oxygen atoms; when R is fluoroalkyl or fluorooxyalkyl group as above defined, it can contain from 1 to 2 atoms, equal or different, selected from the following: H, Cl, Br, I; X═F, H.

[0001] The present invention relates to fluorovinyl ethers, the processfor preparing them and the polymers obtainable therefrom.

[0002] It is well known that perfluoroalkylvinyl ethers are generallyused as monomers for the olefin copolymerization, specificallytetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene(CTFE), hexafluoropropene. The introduction of small amounts ofperfluoroalkylvinyl ethers in plastomeric polymers implies a higherpolymer processability and better hot mechanical properties. Theintroduction of high amounts of perfluorovinyl ethers in crosslinkablefluoropolymers implies elastomeric properties at low temperature offluorinated rubbers.

[0003] The need was felt, in the field of fluorinated polymer materials,to produce elastoamers having improved properties at low temperatures.Such properties can generally be expressed by the glass transitiontemperature T_(g).

[0004] A lower T_(g) allows to have elastomeric polymers which can beused at lower temperatures and therefore to have available elastomerswith a wider use range. To obtain the combination of the above mentionedproperties, fluorovinyl ethers must have a high unitary capability tomodify the base backbone properties, as well as high reactivity to beused as comonomers in elastomeric fluoropolymers. It was desirable tohave available vinyl ethers obtainable by simple processes having alimited number of steps. Preferably it would be desirable to haveavailable a continuous process for preparing said vinyl ethers.

[0005] To solve the above technical problem, fluorovinyl ethers havingdifferent structural properties, have been proposed in the prior art.However from the prior art, hereinafter described, various unsolvedproblems result evident in the perfluorovinylether synthesis and in thepreparation of the corresponding polymers having the combination of theabove mentioned properties.

[0006] U.S. Pat. No. 3,132,123 describes the preparation ofperfluoroalkylvinyl ethers, of the corresponding homopolymers andcopolymers with TFE. Homopolymers are obtained under extremeexperimental conditions, by using polymerization pressures from 4,000 to18,000 atm. The perfluoromethylvinylether (PMVE) homopolymer is anelastomer: the T_(g) is not reported. The general formula of thedescribed vinyl ethers is the following:

CF₂═CFOR^(o) _(F)

[0007] wherein R^(o) _(F) is a perfluoroalkyl radical preferably from 1to 5 carbon atoms. A process for preparing these vinyl ethers isdescribed in U.S. Pat. No. 3,291,843 wherein the starting acylfluorideis salified and pyrolized with carbonates also in the presence ofsolvents. By this process undesired hydrogenated byproducts areobtained.

[0008] U.S. Pat. No. 3,450,684 relates to vinyl ethers having theformula:

CF₂═CFO(CF₂CFX⁰O)_(n), CF₂CF₂X⁰

[0009] wherein X⁰═F, Cl, CF₃, H and n′ can range from 1 to 20. Alsohomopolymers obtained by UV polymerization are reported. The exemplifiedcopolymers are not characterized by their mechanical and elastomericproperties at low temperatures.

[0010] U.S. Pat. No. 3,635,926 relates to the emulsion copolymerizationof perfluorovinyl ethers with TFE, showing that the presence of —COFacylfluoride end groups makes the polymers unstable. The same phenomenonwas already reported in U.S. Pat. No. 3,085,083 in theperfluorovinylether polymerization systems in solvent.

[0011] U.S. Pat. No. 3,817,960 relates to the preparation andpolymerization of perfluorovinyl ethers having the formula

CF₃O(CF₂O)_(n″)CF₂CF₂OCF═CF₂

[0012] wherein n″ can range from 1 to 5. The compound synthesis iscomplex, it requires three steps. The preparation of the startingcompound CF₃O(CF₂O)_(n″)CF₂C(O)F is carried out by oxidation at lowtemperature in the presence of U.V. radiations; besides the condensationwith HFPO (hexafluoropropenoxide) and the subsequent alkaline pyrolisisis necessary. No characterization data on the above indicated propertiesare reported. With regard to this see patent application DE 19,713,806.

[0013] U.S. Pat. No. 3,896,179 relates to the separation of “primary”isomers of perfluorovinylether, for example of CF₃CF₂CF₂OCF═CF₂ from thecorresponding less stable “secondary” isomers CF₃(CF₃)CFOCF═CF₂. Thelatter are undesired products as regards both the polymer preparationand the poor properties of the obtained polymers.

[0014] U.S. Pat. No. 4,340,750 relates to the preparation ofperfluorovinyl ethers having the formula

CF₂═CFOCF₂R^(o) _(f)X¹

[0015] wherein R^(o) _(f) is a C₁-C₂₀ perfluoroalkyl optionallycontaining oxygen, X¹═H, Cl, Br, F, COOR^(o), CONR^(o)R wherein R^(o) isa C₁-C₁₀ alkyl group and R′ represents H or a C₁-C₁₀ alkyl group. In thepreparation of these compounds an acylfluoride together with iodine andtetrafluoroethylene is used, avoiding the final step of the acylfluoridepyrolisis which comes from the perfluoro-propene epoxide, by adeiodofluorination reaction, which takes place with low yields.

[0016] U.S. Pat. No. 4,487,903 relates to the preparation offluoroelastomeric copolymers using perfluorovinyl ethers having theformula:

CF₂═CF(OCF₂CFY^(o))_(n) ^(o)OX²

[0017] wherein n₀ ranges from 1 to 4; Y^(o)═F, Cl, CF₃, H; X² can beC₁-C₃ perfluoroalkyl group, C₁-C₃ ω-hydroperfluoroalkyl group, C₁-C₃ω-chloroperfluoroalkyl group. The polymer has a content offluorovinylether units content ranging from 15 to 50% by moles. Thesevinyl ethers give copolymers which at low temperatures have betterproperties than those of the above mentioned perfluorovinyl ethers PVE(perfluoropropylvinylether) and MVE type. In the patent it is disclosedthat in order to have good properties at low temperature, the presenceof at least two ether bonds in the side chain adjacent to the doublebond is required. Furthermore from the patent it results that for n⁰values higher than 4 it is difficult to purify the monomers and theeffect on the decrease of the polymer Tg is lower. Besides thereactivity of the described vinyl ethers is very low and it is difficultto obtain polymers having a high molecular weight able to give goodelastomeric properties for the indicated applications. A TFE/perfluorovinyl ether copolymer (n^(o)═2) 31/69% by weight with T_(g) of−32° C. is exemplified. However the polymer is obtained with very longreaction times (96 hours of polymerization). Also in this case nocharacterization data of the cured elastomer are given.

[0018] EP 130,052 describes the perfluorovinylpolyether (PVPE)polymerization which leads to amorphous perfluoropolymers with a T_(g)ranging from −15 to −100° C. The described polymers have T_(g) valuesreaching up to −76° C.; the further T_(g) decrease is obtained by usingperfluoropolyethers as plasticizers. In the patent copolymers andterpolymers of TFE and KVE with vinylethers (PVPE) having the formula

CF₂═CFO(CF₂CF(CF₃)0)_(n)′″R^(o) _(f),

[0019] are described, wherein n′″ ranges from 3 to 30 and R^(o) _(f), isa perfluoroalkyl group. Due to purification difficulties, the used vinylethers are vinylether mixtures with different n′″ values. According tosaid patent the most evident effect on the T_(g) decrease is shown whenn′″ is equal to or higher than 3, preferably higher than 4. According tothe polymerization examples described in said patent the final mass ofthe polymer, besides the hot and under vacuum treatment, must then bewashed with freon® TF in order to remove all the unreacted monomer(PVPE). From the Examples it results that the reactivity of all thedescribed monomers (PVPE) is poor.

[0020] U.S. Pat. No. 4,515,989 relates to the preparation of newintermediates for the fluorovinylether synthesis. According to thepatent the vinylether synthesis is improved by using an intermediateable to more easily decarboxylate. For its preparation fluoroepoxides offormula:

[0021] wherein X³═Cl, Br are used.

[0022] U.S. Pat. No. 4,766,190 relates to the polymerization ofperfluorovinylpolyethers (PVPE) similar to those of U.S. Pat. No.4,487,903 with TFE and low perfluoropropene percentages, in order toincrease the mechanical properties of the obtained polymers.

[0023] EP 338,755 relates to the preparation of perfluorinatedcopolymers by using direct fluorination of partially fluorinatedcopolymers. More reactive partially fluorinated monomers are used,subjecting then the obtained polymers to fluorination with elementalfluorine. The fluorination step requires a supplementary process unit,besides in this step elemental fluorine is used, which is a highlyoxidizing gas, with the consequent precautions connected to its use.Besides in the patent it is stated that in order not to compromise thefluorination reaction and the properties of the obtained polymer, usingthe invention process the percentage of the comonomer in the polymercannot exceed 50% by moles.

[0024] U.S. Pat. No. 5,268,405 reports the preparation of perfluorinatedrubbers having a low T_(g), by using high viscosity perfluoropolyethersas plasticizers of perfluorinated rubbers (TFE/MVE copolymers). Howeverduring the use perfluoropolyether bleeds take place. This is trueespecially for the the PFPE having a low molecular weight (lowviscosity): in said patent, therefore, the high viscosity PFPE use issuggested, and therefore the low viscosity PFPES must previously beremoved.

[0025] U.S. Pat. No. 5,350,497 relates to the preparation ofperfluoroalkylvinyl ethers by fluorination with elemental fluorine ofhydrofluorochloroethers and subsequent dechlorination.

[0026] U.S. Pat. No. 5,401,818 relates to the preparation ofperfluorovinyl ethers of formula:

R¹ _(f)(OCF₂CF₂CF₂)_(m), —OCF═CF₂

[0027] (wherein R¹ _(f) is a C₁-C₃ perfluoroalkyl radical and m′ is aninteger ranging from 1 to 4) and of the corresponding copolymers havingimproved properties at low temperature. The preparation of saidperfluorovinyl ethers is carried out by 7 steps, some of them have verylow yields, and comprise also a perfluorination with elemental F₂. Thereactivity of said perfluorovinyl ethers is anyhow low.

[0028] As it is shown from the above reported prior art, theperfluorovinylether synthesis generally involves a multistep processwith low yields (U.S. Pat. No. 3,132,123, U.S. Pat No. 3,450,684), withadditional purifications to remove undesired isomers (U.S. Pat. No.3,896,179) and the need to control the undesired hydrogenatedby-products (U.S. Pat. No. 3,291,843). Alternatively, in the synthesissubstances acting as intermediates, which are suitably prepared, andwhich allow to eliminate said drawbacks (U.S. Pat. No. 4,340,750, U.S.Pat No. 4,515,989), are used.

[0029] Furthermore in some cases the vinylether preparation requires thefluorination with elemental fluorine of partially fluorinatedintermediates (U.S. Pat. No. 5,350,497); or, to avoid synthesis and lowreactivity problems of the perfluorovinyl ethers, fluorination ofpartially fluorinated polymers (EP 338,755) is suggested.

[0030] Other problems shown in the prior art relate to the lowreactivity of the perfluorovinyl ethers, which makes it necessary therecovery of the unreacted monomers from the reaction products (UK1,514,700), and the stability problems for the polymers having —C(O)Fend groups (U.S. Pat. No. 3,635,926). These last can be furtherlytransformed by suitable reactants in order to increase the stability ofthe fluorinated polymer (EP 178,935).

[0031] Perfluorooxyalkylvinyl ethers are furthermore used to confer tothe fluorinated rubbers good properties at low temperatures, andspecifically to lower the glass transition temperature.

[0032] By increasing the perfluorooxyalkyl units forming the sideperfluorooxyalkyl substituent, the T_(g) of the respective obtainableamorphous copolymers decreases, but at the same time the vinyletherreactivity drastically decreases, making it difficult or impossible toobtain polymers having a sufficiently high molecular weight for givingto the polymers the desired elastomeric properties, and besides makingmore evident the problems previously shown for the recovery of theunreacted monomer from the polymerization raw products or from thepolymer itself (U.S. Pat. No. 4,487,903- EP 130,052). In some cases,where the monomer cannot be completely removed by simple stripping undervacuum, more washings must then be carried out with fluorinated solventsfor completely eliminating the unreacted vinylether from the polymermass.

[0033] The amorphous copolymers of TFE with perfluoromethylvinyletherhave a T_(g) around 0° C. or slightly lower (Maskornik, M. et al.“ECD-006 Fluoroelastomer-A high performance engineering material”. Soc.Plast Eng. Tech. Pao. (1974), 20, 675-7).

[0034] The T_(g) extrapolated value of the MVE homopolymer is of about−5° C. (J. Macromol. Sci.-Phys., B1(4), 815-830, Dec. 1967).

[0035] In U.S. Pat. No. 5,296,617 and 5,235,074 there is described thehypofluorite CF₂(OF)₂ reactivity towards unsaturated products, whichcontemporaneously leads to the formation of the dioxolane derivative andto the fluorination compound of the olefin itself. In EP 683,181 thereis described the CF₂(OF)₂ reactivity towards olefins which leads to theformation of linear reaction compound between one hypofluorite moleculeand two molecules of the same olefin, for the preparation of symmetricdienes.

[0036] More specifically fluoroelastomers, suitable to the preparationof O-rings, based on monomeric units deriving from vinylidenfluoride(VDF), hexafluorapropene (HFP), perfluoroalkylvinyl ethers (PAVE) suchas for example methylvinyl ether, and optionally tetrafluoroethylene(TFE), which are curable by ionic route, have high elastomericproperties at low and high temperatures and show good processability, atthe mould release after curing (see U.S. Pat. No. 5,260,393). Saidfluoroelastomers show improved properties with respect to the copolymersformed by VFD and HFP units, used in the O-ring preparation. In factsaid last copolymers show good hot properties, but poor properties atlow temperatures.

[0037] It is also known that fluoroelastomers having better coldproperties are those based on VDF, PAVE and optionally TFE units,curable by radical route with peroxides and crosslinking agents.

[0038] By this kind of crosslinking, however, the process for producingmanufactured articles is more complex with respect to the crosslinkingof ionic type.

[0039] Fluoroelastomeric copolymers based on monomeric units derivingfrom vinylidenfluoride (VDF), which are curable by ionic route andsuitable for the production of shaft seals and fuel hoses (see U.S. Pat.No. 5,260,392), are also known.

[0040] As it is known, the preparation of such manufactured articlesrequires elastomeric materials having an optimal combination of thefollowing properties: good resistance properties to motor oils and/orpetrols, good resistance properties at high temperatures as well as goodcold behaviour and in particular, for the manufactured articles as shaftseals, good processability in both compression and injection mouldingand also good curing rate.

[0041] It is known to use for such manufactured articlesfluoroelastomeric copolymers formed by monomeric units of VDF,perfluoroalkylvinyl ethers (PAVE) and tetrafluoroethylene (TFE).

[0042] Said copolymers have good properties at low temperatures, howeverthey show the drawback to be curable only by peroxidic route, with allthe drawbacks due to said curing method, such as for example the need tocarefully control the temperatures in the compounding operations, theshort scorch and thermal activation times.

[0043] Fluoroelastomers having an improved processability and very goodmechanical and elastic properties curable both by ionic and peroxidicroute, are also known.

[0044] It is also known that an improvement in the fluoroelasomerprocessability is obtainable by suitably mixing polymers having adifferent molecular weight distribution. This inevitably implies,besides swelling phenomena after extrusion, a worsening in themechanical properties and in the final product mouldability.

[0045] Said fluoroelastomers show an improved processability, especiallyduring the blend calendering, combined with very good mechanical andworkability properties during the extrusion and the injection moulding,together with a very good mould release. These fluoroelastomers areobtained by introducing in the polymer chain small amounts of abis-olefin (see U.S. Pat. No. 5,585,449). The above describedfluoroelastomers have however the drawback to show at low temperaturesproperties not yet able to satisfy the most urgent requirements ofresistance at low temperatures, such as for example in car industry,wherein materials are required having the combination of the followingproperties:

[0046] chemical resistance to petrols additived with alcohols or MBTE orother polar compounds,

[0047] high resistance at low temperatures such as for example shown byTR 10 (ASTM D 1329 method),

[0048] very low T_(g),

[0049] maintenance of good elastomeric properties, such as for examplemechanical and sealing properties, in particular at high temperatures.

[0050] The Applicant has surprisingly and unexpectedly found that it ispossible to solve the above technical problem as described hereinafter,by using special fluorovinyl ethers, which are furthermore easilysynthetizable and obtainable by a continuous process.

[0051] An object of the present invention are fluoroelastomers that iselastomeric fluoropolymers, comprising in the polymer chain unitsderiving from fluorovinyl ethers of general formula:

CFX═CXOCF₂OR  (I)

[0052] wherein R is a C₂-C₆ linear, branched or C₅-C₆ cyclic(per)fluoroalkyl group, or a C₂-C₆ linear, branched (per)fluorooxyalkylgroup containing from one to three oxygen atoms; when R is a fluoroalkylor fluorooxyalkyl group as above defined it can contain from 1 to 2atoms, equal or different, selected from the following: H, Cl, Br, andI; X═F, H.

[0053] The fluorovinyl ethers of general formula:

CFX═CXOCF₂OCF₂CF₂Y  (II)

[0054] wherein Y═F, OCF₃; X is as above defined, are preferred among thecompounds of formula (I).

[0055] The perfluorovinyl ethers of formula:

CF₂═CFOCF₂OCF₂CF₂Y  (III)

[0056] wherein Y is as above defined, are particularly preferred.

[0057] The perfluorovinylether having the formula:

CF₂═CFOCF₂OCF₂CF₃  (IV)

[0058] is still furtherly preferred.

[0059] Surprisingly, the vinyl ethers according to the invention showthe advantages reported hereinafter with respect to the known vinylethers.

[0060] The obtainable advantages can be attributed to the —OCF₂O— unitdirectly bound to the ethylene unsaturation.

[0061] The T_(g) lowering obtained with the vinyl ethers of theinvention is connected to the presence of the (—OCF₂O—) unit directlybound to the unsaturation. The T_(g) lowering is surprisingly so evidentto be defined a primary effect.

[0062] In fact if the vinylether of the invention with two oxygen atomsis used:

CF₂═CF—O—CF₂—O—CF₂CF₃  (MOVE 1)

[0063] the T_(g) lowering, in copolymers with TFE having vinyletherpercentages of about 46% by weight is of 35° C. with respect to PVE

CF₂═CF—O—CF₂CF₂CF₃  (PVE)

[0064] and of 15° C. with respect to the vinylether having the sameempirical formula, but with the second oxygen atom in a differentposition and without showing the characteristic unit (—OCF₂O—)

CF₂═CF—O—CF₂CF₂O—CF₃  (β-PDE)

[0065] It is still more surprising to notice that with respect to MVE

CF₂═CF—O—CF₃

[0066] the β-PDE vinylether does not give any advantage as regardsT_(g).

[0067] On the contrary the primary effect of the (—OCF₂O—) unit resultsvery clear with the vinyl ethers of the invention (MOVE).

[0068] It has been found that the (—OCF₂O—) unit bound to the ethyleneunsaturation of the vinyl ethers of the invention increases thevinylether reactivity, reducing the rearrangements to COF which causeinstability.

[0069] The advantages of the polymers of the invention can be summarizedas follows:

[0070] The reactivity of the new monomers allows to prepare copolymershaving a very low content of carboxylic groups or derivatives thereofsuch as —C(O)F, —COO—. The carboxylic group content in the copolymerwith TFE has resulted of about 10 times lower than that of a copolymerprepared under the same conditions but using PVE instead of fluorovinylethers (see the Examples). As said, the presence of a lower content ofcarboxylic groups, or of the corresponding derivatives (amides, esters,etc.) allows to obtain more stable polymers.

[0071] The reactivity of the monomers of formula (I) is surprisinglyhigh (see the Examples).

[0072] To obtain amorphous polymers the amount of the vinylether of theinvention must be such to lead to the disappearance of the crystallinedomains. That is, the polymer is substantially free of crystallinedomains. The skilled man in the art can easily verify the amount of thevinyl ethers of the invention which is required for obtaining saidresults. Generally the amount of the vinylether for obtaining amorphouspolymers is higher than 10% by moles, (i.e. 10 mole %) preferably in therange from about 15 to 20% by moles, or higher.

[0073] The properties at low temperature (T_(g)) of the polymers objectof the invention result clearly better with respect both to copolymershaving the same MVE content (see the Examples) and also, surprisingly,with respect to copolymers where the perfluorovinylether, the oxygenatoms being equal, does not show the —OCF₂O— group directly bound to theunsaturation, as in the case of the CF₂═CFOCF₂CF₂OCF₃ (β-PDE)(see theExamples).

[0074] A further advantage of the fluorovinyl ethers (I) of theinvention, as hereinafter illustrated, consists in that theirpreparation is carried out in a continuous manner by a limited number ofsteps. Furthermore the used raw materials are inexpensive. The followingones can for example be mentioned: CF₂(OF)₂, CF₂═CF₂, CF₂═CFOCF₃,CHC1═CFC1, CFC1═CFC1, CF₂═CFC1, CF₂═CFH, CF₂═CH₂, CHC1═CHC1 and otherolefins.

[0075] The use of these reactants is specified in the synthesis processof the vinyl ethers of the invention.

[0076] The copolymers of the invention are obtainable by polymerizingwith suitable comonomers, the fluorovinyl ethers of general formula(I)-(IV). To obtain the fluoroelastomers of the invention the amount ofthe comonomers of formula (I)-(IV) used in the comonomer mixture is suchto lead to the disappearance of the crystalline domains. Generally theamount is higher than 10% by moles.

[0077] When used in connection with a quantity the term about refers tosuch normal variation in that quantity as would be expected by theskilled artisan.

[0078] As used herein, essentially free of crystalline zones or regionsmeans that crystallinity is not detected by, for example, DSC, undertypical ordinary conditions as would be used by the skilled artisan inroutine experiments.

[0079] With copolymer, a polymer containing the vinyl ether of theinvention and one or more comonomers, is meant.

[0080] Preferred comonomers are fluorinated compounds having at leastone polymerizable carbon-carbon double bond C═C, optionally containinghydrogen and/or chlorine and/or bromine and/or iodine and/or oxygen.

[0081] Other comonomers that can be copolymerized withn the fluorovinylethers of the present invention are non fluorinated C₂-C₈ olefins, i.e.olefinically unsulated hydrocarbons such as ethylene, propylene, andisobutylene.

[0082] The following are some examples of suitable copolymerizablecomonomers, as that term is used herein, and others will be in thecontemplation of the skilled artisan:

[0083] C₂-C₈ perfluoroolefins, such as tetrafluoroethylene (TFE)hexafluoropropene (HFP), hexafluoroisobutene;

[0084] C₂-C₈ hydrogenated fluoroolefins, such as vinyl fluoride (VF),vinylidene fluoride (VDF), trifluoroethylene,

[0085] CH₂═CH—R² _(f) perfluoroalkylethylenes wherein R²f is a C₁-C₆perfluoroalkyl;

[0086] C₂-C₈ chloro- and/or bromo- and/or iodo-fluoroolefins, such aschlorotrifluoroethylene (CTFE) and bromotri-fluoroethylene;

[0087] CF₂═CFOR² _(f) (per)fluoroalkylvinyl ethers (PAVE), wherein R²_(f) is a C₁-C₆ (per)fluoroalkyl, for example trifluoromethyl,bromodifluoromethyl or heptafluoropropyl;

[0088] CF₂═CFOX^(a) (per)fluoro-oxyalkylvinyl ethers, wherein X^(a) is aC₁-C₁₂ alkyl, or a C₁-C₁₂ oxyalkyl, or a C₁-C₁₂ (per)fluorooxyalkylhaving one or more ether groups, for example perfluoro-2-propoxy-propyl.

[0089] sulphonic monomers having the structure CF₂═CFOX^(b)SO₂F, whereinX^(b)═CF₂CF₂, CF₂CF₂CF₂, CF₂CF(CFX^(C)) wherein X^(c)═F, Cl, Br.

[0090] a bis-olefin having the general formula

R^(I) ₁, R^(I) ₂, C═CR^(I) ₃,—Z—CR^(I) ₄═CR^(I) ₅R^(I) ₆,  (IA)

[0091] wherein

[0092] R^(I) ₁, R^(I) ₂, R^(I) ₃, R^(I) ₄, R^(I) ₅, R^(I) ₆, equal to ordifferent from each other, are H or C₁-C₅ alkyls;

[0093] Z is a C₁-C₁₈ linear or branched alkylene or cycloalkyleneradical, optionally containing oxygen atoms, preferably

[0094] at least partially fluorinated, or a (per)fluoropolyoxy-alkyleneradical.

[0095] In the formula (IA), Z is preferably a C₄-C₁₂ perfluoro-alkyleneradical, while R^(I) ₁ , R^(I) ₂, R^(I) ₃, R^(I) ₄, R^(I) ₅, R^(I) ₆ arepreferably hydrogen.

[0096] When Z is a (per) fluoropolyoxyalkylene radical, it preferablyhas the formula:

—(Q)_(p)—CF₂O—(CF₂CF₂O)_(ma)(CF₂O)_(na)—CF₂—(Q)_(p)—  (IIA)

[0097] wherein:

[0098] Q is a C₁-C₁₀ alkylene or oxyalkylene radical;

[0099] p is 0 or 1;

[0100] ma and na are integers such that the ma/na ratio is comprisedbetween 0.2 and 5 and the molecular weight of said(per)fluoropolyoxyalkylene radical is in the range from 500 to 10,000,preferably from 1,000 to 4,000.

[0101] Preferably, Q is selected from the following groups:

—CH₂OCH₂—; —CH₂O(CH₂CH₂O)_(s)CH₂—,

[0102] with s =1-3.

[0103] The bis-olefins of formula (IA) wherein Z is an alkylene orcycloalkylene radical can be prepared according to what described, forexample, by I. L. Knunyants et al. in Izv. Akad. Nauk. SSR, Ser. Khim.1964(2), 384-6, while the bis-olefins containing(per)fluoropolyoxyalkylene sequences are described in USP 3,810,874.

[0104] The amount of units in the chain deriving from said bis-olefinsis generally in the range 0.01-1.0 by moles.

[0105] The above indicated comonomers, polymerizable with perfluorovinylethers, can be used separately or in admixture with other comonomers.

[0106] The base structure of the fluoroelastomer can in particular beselected from:

[0107] (1) copolymers based on VDF, wherein the latter is copolymerizedwith at least one copolymerizable comonomer selected from:

[0108] C₂-C₈ perfluoroolefins such as tetrafluoroethylene (TFE),hexafluoropropene (HFP) C₂-C₈ chloro- and/or bromo and/oriodo-fluoroolefins, such as chlorotrifluoroethyethylene (CTFE) andbromotrifluoroethylene; CF₂═CFOR^(t) _(f) (per)fluoroalkylvinyl ethers(PAVE), wherein R^(t) _(f) is a C₁-C₆ (per)fluoroalkyl, for exampletrifluoromethyl, bromodifluoromethyl, pentafluoropropyl; CF₂═CFOX^(t)perfluorooxyalkylvinyl ethers, wherein X^(t) is a C₁-C₁₂perfluorooxyalkyl having one or more ether groups, for exampleperfluoro-2-propoxy-propyl; C₂-C₈ non fluorinated olefins (01), forexample ethylene and propylene;

[0109] (2) copolymers based on TFE, where the latter is copolymerizedwith at least one copolymerizable comonomer selected from:

[0110] CF₂═CFOR^(t) _(f) (per)fluoroalkylvinyl ethers (PAVE), whereinRtf is as above defined; CF₂═CFOX^(t) perfluorooxyalkylvinyl ethers,wherein X^(t) is as above defined; C₂-C₈ fluoroolefins containinghydrogen and/or chlorine and/or bromine and/or iodine atoms;

[0111] C₂-C₈ non fluorinated olefins (01).

[0112] Inside the above defined classes of fluoroelastomers, preferredbase monomeric compositions (by moles) are the following: VDF 45-85 HFPand/or PAVE  0-45 TFE  0-30 MOVE  1-45, preferably 5-40 01  0-40 the sumof HFP + PAVE + MOVE being at most 45%; TFE 50-85 PAVE  0-50 MOVE  1-50,preferably 5-40 01  0-40

[0113] the sum of PAVE+MOVE being at most 50.

[0114] The fluoroelastomers of the invention are preferably cured byperoxidic route.

[0115] When they are cured by ionic route, the preferred compositions(expressed by moles) are the following when the fluoroelastomer is usedfor the O-Ring preparation: VDF 48-65 HFP 20-35 PAVE 0-6 TFE  0-20 MOVE3-9

[0116] the SUM PAVE +MOVE lower than or equal to 10% by moles.

[0117] For the use of fluoroelastomers for obtaining shaft seals or fuelhoses the following compositions (by moles) are preferred: VDF 30-47 HFP20-40 PAVE  0-17 TFE 10-30 MOVE  3-20

[0118] the sum PAVE+MOVE lower than or equal to 20% by moles.

[0119] In the case of fluoroelastomers curable by peroxidic route, it ispreferable to add small amounts of a bis-olefin as above mentioned.

[0120] In order to reach a good curing degree it is suitable to usefluoroelastomers containing reactive sites, i.e. iodine and/or brominein chain, preferably iodine (cure site monomer).

[0121] Also an iodinated and/or brominated transfer agent can be used.

[0122] The process for the preparation of fluorinated polymers accordingto the present invention can be carried out by polymerization in organicsolvent as described in U.S. Pat. Nos. 4,864,006 and 5,182,342, hereinincorporated by reference. The organic solvent is selected from thegroup comprising chlorofluorocarbons, perfluoropolyethers,hydrofluorocarbons and hydrofluoroethers.

[0123] Alternatively the preparation of fluoroelastomers object of thepresent invention can be carried out by copolymerization of the monomersin aqueous emulsion according to well known methods in the prior art, inthe presence of radical initiators (for example alkaline or ammoniumpersulphates, perphosphates, perborates or percarbonates), optionally incombination with ferrous, cuprous or silver salts, or of other easilyoxidizable metals. In the reaction medium also surfactants of varioustype are usually present, among which the fluorinated surfactants offormula:

R³ _(f)—X⁻M⁺

[0124] are particularly preferred, wherein R³ _(f) is a C₅-C₁₆(per)fluoroalkyl chain or a (per) fluoropolyoxyalkyl chain, X⁻ is —COO⁻or —SO₃ ⁻, M⁺is selected from: H⁺, NH₄ ⁺, an alkaline metal ion. Amongthe most commonly used, ammonium perfluorooctanoate,(per)fluoropolyoxyalkylenes ended with one or more carboxylic groups,etc. can be mentioned.

[0125] See U.S. Pat. No. 4,990,283 and U.S. Pat. No. 4,864,006.

[0126] At the end of the polymerization, the fluoroelastomer isseparated from the emulsion by conventional methods, such as coagulationby addition of electrolytes or by cooling.

[0127] Alternatively, the polymerization can be carried out in bulk orin suspension, in an organic liquid where a radical initiator ispresent, according to well known techniques.

[0128] The polymerization reaction is generally carried out attemperatures comprised between 25° C. and 150° C., under pressure up to10 MPa.

[0129] The preparation of the fluoroelastomers of the present inventionis preferably carried out in aqueous emulsion in the presence of anemulsion, dispersion or microemulsion of perfluoropolyoxyalkylenes,according to U.S. Pat. No. 4,789,717 and U.S. Pat. No. 4,864,006.

[0130] The fluoroelastomers of the present invention are preferablycured by peroxidic route, wherefore they preferably contain in the chainand/or in terminal position of the macromolecules iodine and/or bromineatoms, preferably iodine. The introduction of such iodine and/or bromineatoms can be carried out by addition, in the reaction mixture, ofbrominated and/or iodinated cure-site comonomers, such as bromo and/oriodo olefins having from 2 to 10 carbon atoms (as described for examplein U.S. Pat. No. 4,035,165 and U.S. Pat. No. 4,694,045), or iodo and/orbromo fluoroalkylvinyl ethers (as described in patents U.S. Pat. No.4,745,165, U.S. Pat. No. 4,564,662 and EP 199,138), in amounts such thatthe content of cure-site comonomers in the final product is generally inthe range 0.05-2 moles for 100 moles of the other base monomeric units.

[0131] Alternatively or also in combination with cure-site comonomers,it is possible to introduce iodine and/or bromine end atoms by additionto the reaction mixture of iodinated and/or brominated chain transferagents, such as for example compounds of formula R^(b)_(f)(I)_(x)(Br)_(y), wherein R^(b) _(f) is a (per)fluoroalkyl or a(per)fluorochloroalkyl having from 1 to 8 carbon atoms, while x and yare integers comprised between 0 and 2, with 1≦x+y ≦2 (see for examplepatents U.S. Pat. No. 4,243,770 and U.S. Pat. No. 4,943,622).

[0132] It is also possible to use as chain transfer agents iodidesand/or bromides of alkaline or alkaline-earth metals, according to U.S.Pat. No. 5,173,553.

[0133] Alternatively or in combination with the chain transfer agentscontaining iodine and/or bromine, other chain transfer agents known inthe prior art, such as ethyl acetate, diethylmalonate, etc., can beused.

[0134] Curing by peroxidic route is carried out, according to knowntechniques, by addition of a suitable peroxide able to generate radicalsby heating.

[0135] Among the most commonly used we remind: dialkylperoxides, such asfor example di-terbutyl-peroxide and2,5-dimethyl-2,5-di(terbutylperoxy)hexane; dicumyl peroxide, dibenzoylperoxide; diterbutyl perbenzoate;di-[1,3-dimethyl-3-(terbutylperoxy)butyl]carbonate. Other peroxidicsystems are described, for example, in European patent applications EP136,596 and EP 410,351.

[0136] To the curing blend other compounds are then added, such as:

[0137] (a) curing coagents, in amounts generally in the range 0.5-10%,preferably 1-7%, by weight with respect to the polymer; among them:triallyl-cyanurate, triallyl isocyanurate (TAIC),tris(diallylamine)-s-triazine; triallylphosphite;N,N-diallyl-acrylamide;

[0138] N,N,N′,N′-tetraallyl-malonamide; tri-vinyl-isocyanurate; and4,6-tri-vinyl-methyltrisiloxane, etc. are commonly used: TAIC isparticularly preferred;

[0139] (b) a metal compound, in amounts in the range 1-15%, preferably2-10%, by weight with respect to the polymer, selected from oxides andhydroxides of divalent metals, such as for example Mg, Zn, Ca or Pb,optionally combined with a weak acid salt, such as for examplestearates, benzoates, carbonates, oxalates or phosphites of Ba, Na, K,Pb, Ca;

[0140] (c) other conventional additives, such as thickeners, pigments,antioxidants, stabilizers and the like.

[0141] The fluoroelastomers of the present invention can be cured byionic route. Suitable well known in the art curing and acceleratingagents are added to the curing blend, besides the above mentionedproducts at points (b) and (c). For example, as curing agents aromaticor aliphatic polyhydroxylated compounds, or derivatives thereof can beused, as described for example in EP 335,705 and U.S. Pat. No.4,233,427. Among them it can in particular be mentioned: di-, tri- andtetra-hydroxybenzenes, naphthalenes or anthracenes; bisphenols whereinthe two aromatic rings are linked each other by an aliphatic,cycloaliphatic or aromatic bivalent radical, or by one oxygen or sulphuratom, or also one carbonyl group. The aromatic rings can be replacedwith one or more chlorine, fluorine, bromine atoms, or with carbonyl,alkyl, acyl.

[0142] As accelerants it can for example be used: ammonium, phosphonium,arsonium or antimony quaternary salts (see for example EP 335,705 andU.S. Pat. No. 3,876,654); amino-phosphonium salts (see for example U.S.Pat. No. 4,259,463); phosphoranes (see for example U.S. Pat. No.3,752,787); the iminic compounds described in EP 182,299 and EP 120,462;etc. Also adducts between an accelerant and a curing agent can be used,see patents U.S. Pat. No. 5,648,429, U.S. Pat. No. 5,430,381, U.S. Pat.No. 5,648,430 herein incorporated by reference.

[0143] It is also possible to use systems of mixed, both ionic andperoxidic, curing, as described in EP 136,596.

[0144] The synthesis process of the new (per) fluorovinyl ethers, whichcomprises the initial reaction of the hypofluorite with a fluorinatedolefin of formula R₁R₂C═CR₃R₄ to give the intermediate hypofluoriteF—CR₁R₂—CR₃R₄—OCF₂OF, the subsequent reaction of said compound with asecond fluorinated olefin of formula R₅R₆C═CR₇R₈ to give theintermediate F—CR₁R₂—CR₃R₄—OCF₂O—CR₅R₆—CR₇R₈—F which by dehalogenationor dehydrohalogenation leads to the new perfluorovinyl ethers.

[0145] The general scheme of the synthesis is the following:

a) CF₂(OF)₂+R₁R₂C=CR₃R₄→F−CR₁R₂−CR₃R₄−OCF₂OF  (VI)

b) F−CR₁R₂−Cr₃R_(4−OCF) ₂OF=R₅R₆C²=C¹R₇R₈- - - →F−CR₁R₂−CR₃R₄−OCF_(2O−C)²R₅R₆−C¹R₇R₈−F dehalogen./  (VII)

c) F−CR₁R₂−CR₃R₄−OCF₂0−C²R₅R₆−C¹R₇R₈−F - - - →, /dehydrohalogen.

CFX=CXOCF₂OR  (I)

[0146] In this synthesis scheme:

[0147] with reference to the formula of the compound (VII):

[0148] R₁, R4, equal or different, are H, F; R₂, R₃, equal or differentare H, Cl under the following conditions: (1) when the final reaction isa dehalogenation R₂, R₃═Cl, (2) when the final reaction is adehydrohalogenation one of the two substituents R₂, R₃ is H and theother is Cl; R₅, R₆, R₇, R₈ are:

[0149] F, or one of them is a C₁-C₄ linear or branched perfluoroalkylgroup, or a C₁-C₄ linear or branched perfluorooxyalkyl group containingfrom one to three oxygen atoms, or R₅ and R₇, or R₆ and R₈, are linkedeach other to form with C² and C¹ a C₅-C₆ cycle perfluoroalkyl group;

[0150] when one of the R₅-R₈, radicals is a C₂-C₄ linear or branchedfluoroalkyl, or a C₂-C₄ linear or branched fluorooxyalkyl containingfrom one to three oxygen atoms, one or two of the other R₅-R8 are F andone or two of the remainders, equal to or different from each other, areselected from H, Cl, Br, Iodine; when the substituents selected from H,Cl, Br, Iodine are two, they are both linked to the same carbon atom;when R₅ and R₇, or R₆ and R₈, are linked each other to form with C² andC¹ a C₅-C₆ cycle fluoroalkyl group, one of the two free substituents R₆,R₈ or R₅, R₇ is F and the other is selected from H, Cl, Br, Iodine.

[0151] the fluoroalkene used in the reaction a) is replaceable with thatof the subsequent reaction b); in this case the meanings defined for thesubstituents of the R₁-R₄ group, and respectively of the R₅-R₈ group,are interchangeable each other, with the proviso that the position ofeach radical of each of the two groups R₁-R₄ and R₅-R₈ with respect to—OCF₂O— on the chain of the intermediate compound (VII), is the samewhich is occupied if the synthesis takes place according to the abovereported scheme and the two olefins each react in the considered steps.

[0152] In the first reaction a) of the above illustrated scheme ahypofluorite gas flow CF₂(OF)₂, suitably diluted with an inert fluid,comes into contact, in a suitable reactor with outlet, on the bottom ofthe same (first reactor), with a flow formed by the R₁R₂C═CR₃R₄ olefin,optionally diluted in an inert fluid, so as to allow the chemicalreaction a) with formation of the intermediate hypofluorite (VI). Tofavour the reaction stoichiometry, the reactants must be introduced intothe reactor in an approximately unitary molar ratio, or with an excessof CF₂(OF)₂. The residence time of the mixture in the reactor can rangefrom few hundredths of second up to about 120 seconds depending on theolefin reactivity, the reaction temperature and the presence of optionalreaction solvents.

[0153] The reaction temperature can range from −40° to −150° C.,preferably from −80° to −130° C.

[0154] The compound (VI) usually is not separated from the reactionproduct and it is transferred in a continuous way to the subsequentreaction described in step b).

[0155] The mixture of the products coming out from the first reactor canbe heated at room temperature before being fed into the second reactor.

[0156] In the second reaction b) the second olefin R₅R6C═CR₇R₈ pure orin solution, reacts with the product obtained in the first reaction withformation of compound (VII).

[0157] The olefin can be fed in a continuous way, so as to maintain itsconcentration constant in the reactor. The temperature of the reactionb) can range from −20° to −130° C., preferably from −50° to −100° C. Theolefin concentration is higher than or equal to 0.01 M, preferably theconcentration is higher than 3 M, more preferably also the pure compoundcan be used.

[0158] The solvents used in steps a) and b) are perfluorinated orchlorohydrofluorinated solvents or hydrofluorocarbons. Examples of saidsolvents are: CF₂Cl₂, CFCl₃, CF₃CF₂H, CF₃CFH₂, CF₃CF₂CF₃, CF₃CCl₂H,CF₃CF₂Cl. In the reaction c) the compound (VII), dependently on theolefins used in steps a) and b), after distillation from the reactionraw product, is subjected to dechlorination or to dehydrochlorination toobtain the vinyl ethers of formula (I). This last step can be carriedout by using reactions widely described in the prior art. The suitableselection of the substituents R₁ to R₈ in the two olefins used in thesynthesis allows to obtain the vinyl ethers of the present invention.

[0159] Another object of the invention is a process wherein ahypofluorite of formula X₁X₂C(OF)₂ wherein X₁ and X₂ equal or differentare F, CF₃, and two fluoroalkenes of formula respectively R^(A) ₁R^(A)₂C═CR^(A) ₃R^(A) ₄ and R^(A) ₅R^(A) ₆C═CR^(A) ₇R^(A) ₈ wherein R^(A)₁R^(A) ₈equal or different, are F, H, Cl, Br, I, —CF₂OSO₂F, —SO₂F,—COF,C₁-C₅ linear or branched perfluoroalkyl or oxyperfluoroalkyl group, arereacted according to steps a) and b) of the above indicated scheme ofsynthesis, excluding the dehalogenation or dehydrohalogenation step, toobtain compounds of general formula (VIII)

F—CR^(A) ₁R^(A) ₂—CR^(A) ₃R^(A) ₄—OCF₂O—CR^(A) ₅R^(A) ₆—CR^(A) ₇R^(A)₈—F.

[0160] The following Examples are reported with the purpose toillustrate the invention and they do not limit the scope of the same.

[0161] In the Examples the thermogravimetric analysis TGA is carried outby using a 10° C./min rate.

EXAMPLE 1

[0162] Synthesis of CF₃CF ₂OCF₂OCFClCF₂Clperfluoro-1-2,dichloro-3,5-dioxaheptane.

[0163] The used reactor is of cylindrical type, with a total volume of300 ml and is equipped with magnetic dragging mechanical stirrer,turbine with recycle of the reacting gas placed at 20 cm from thereactor top, internal thermocouple, two internal copper pipes for thereactant feeding which end at about 1 mm from the turbine, and productoutlet from the bottom. In the reactor, inside which the temperature ismaintained at −114° C., 1.1 1/h (litres/hour) of CF₂(OF)₂ and 3.3 1/h ofHe are introduced through one of the two inlet pipes; A flow of 1.1 1/hof CF₂═CF₂ and 0.7 1/h of He is maintained through the second inletpipe. Feeding is continued for 6.6 hours.

[0164] The residence time of the transport gas in the reaction zonecomprised between the outlet of the two feeding pipes in the reactor andthe inlet of the discharge pipe is of about 4 sec.

[0165] On the reactor bottom the reaction products are brought again toroom temperature and the gaseous mixture flow, monitored bygaschromatography, is fed in a continuous way, under mechanicalstirring, into a second reactor having a 250 ml volume maintained at thetemperature of —70° C., equipped with mechanical stirrer, thermocouple,dipping inlet for the reacting mixture, outlet with head of inert gas.The reactor contains 72.6 g of dichlorodifluoroethylene CFCl═CFCl.

[0166] At the end of the addition of reacting gases into the secondreactor, the reaction raw material is distilled by a plate column atatmospheric pressure, collecting 41.5 g of the desired product (boilingpoint 91° C.).

[0167] The yield of perfluoro-1,2 dichloro-3,5-dioxaheptane, calculatedwith respect to CF₂(OF)₂, is of 36%.

[0168] Characterization of perfluoro 1,2, dichloro-3,5-dioxaheptane.

[0169] Boiling point at atmospheric pressure: 91° C.

[0170]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃=0):

[0171] −51.3/−53.0 (2F, O—CF₂—O); −70. 6/−72.6 (2F, C—CF₂Cl);

[0172] −78.0/−78.4 (1F, O—CFC1—C); −87.8 (3F, CF₃—C):

[0173] −90.2 /−91.8 (2F, C—CF₂—O).

[0174] Mass spectrum (E.I. electronic impact), main peaks and respectiveintensities:

[0175] 69 (48.6%); 119 (84.3%); 151 (76.8%); 153 (69.8%); 185 (100%).

[0176] IR spectrum (cm⁻¹) intensity: (w)=weak, (m)=medium, (s)=strong,(vs)=very strong:

[0177] 1407.3 (w); 1235.8 (vs); 1177.7 (vs); 1097.5 (vs); 1032.2 (s);929.3 (w); 847. 9 (m)

EXAMPLE 2

[0178] Synthesis of CF₃OCF₂CF₂OCF₂OCFClCF₂Clperfluoro-1,2-dichloro3,5,8-trioxanonane (isomer A) and of CF₃OCF(CF₃)OCF₂OCFClCF₂Cl perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane(isomer B)

[0179] In a reactor identical to that used in Example 1, maintained atthe same temperature of −114° C., 1.55 1/h of CF₂(OF)₂ and 4.5 1/h of Heare introduced through one of the two inlet pipes; through the secondinlet pipe 1.4 1/h of CF₂═CF—OCF₃ and 0.7 1/h of He for 4.5 hours.

[0180] The residence time of the transport gas in the reaction zonecomprised between the reactor outlet and the end of the two feedingpipes is of about 3 sec.

[0181] On the reactor bottom the reaction products are brought to roomtemperature and the gaseous mixture flow, monitored bygaschromatography, is fed in a continuous way, under mechanicalstirring, into a second reactor identical to the one used for the samestep in Example 1. Inside, where a temperature of −70° C. is maintained,there are 51 g of dichlorofluoroethylene CFCl═CFCl.

[0182] At the end of the addition of the reacting gases into the secondreactor, the reaction raw material is distilled by a plate column at thereduced pressure of 250 mmHg. 50 g of a mixture formed by two isomers,respectively, isomer A) perfluoro-1,2-dichloro-3,5,8-trioxanonane andisomer B) perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane arecollected. The mixture composition is determined by gaschromatographyand is the following: isomer A 79%, isomer B 21%. The molar yield of A+Bwith respect to the used CF₂(OF)₂ is 38%. The molar yield of A+B withrespect to the used perfluoromethylvinylether is 42%. The isomers havebeen separated by preparative gaschromatography.

[0183] Characterization of products A and B

[0184] Mixture boiling point (A 79%, B 21%) at the reduced pressure of250 mmHg: 82° C.

[0185]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃=0) of the isomerA: −50.6/−52.4(2F, O—CF₂—O) −70.0/−71.8(2F, C—CF₂Cl); −77.7(1F,O—CFCl—C); −55.3/−55.6(3F, CF₃—OC); −90.7/−91.1(2F, C—OCF₂—C)−90.2/−90.6(2F, C—OC—CF₂OCOC).

[0186]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃=0) of isomer B:−50.0/−52.1(2F, O—CF₂—O)  −70.0/−71.8(2F, C—CF₂Cl) −77.9(IF, O—CFCl—C); −54.6/−54.9(3F, CF₃OC): −85.7/−86.1(3F, OC(CF₃)O) −100.3/−101.0(IF,OCF(C)O).

[0187] Mass spectrum (electronic impact), main peaks and respectiveintensities:

[0188] Product A: 69 (50); 119 (100); 151 (50); 185 (42); 251 (38);

[0189] Product B: 69 (96); 97 (50); 135 (42); 151 (92); 185 (100).

[0190] IR spectrum (cm⁻¹) intensity of the mixture A 79%, B 21%:(w)=weak, (m)=medium, (s)=strong, (vs)=very strong: 1388 (w); 1288 (vs);1233 (vs); 1151 (vs); 1104 (vs); 1032 (s); 846 (m); 685 (w)

EXAMPLE 3

[0191] Synthesis of CF₃OCF₂CF₂OCF₂OCHClCHFCl perfluoro-12-dichloro-1,2-dihydro-3,5,8-trioxanonane (isomer C) and ofCF₃OCF(CF₃)OCF₂OCHClCHFC1perfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane (isomerD).

[0192] In a reactor identical to that used in Example 1, maintained atthe temperature of −112° C., 1.55 1/h of CF₂(OF₂, and 4.5 1/h of He areintroduced through one of the two inlet pipes; through the second inletpipe 1.4 1/h of CF₂═CF—OCF₃ and 0.7 1/h of He for 5 hours.

[0193] The residence time of the transport gas in the reaction zonecomprised between the reactor outlet and the end of the two feedingpipes is of about 3 sec.

[0194] On the reactor bottom the reaction products are brought again toroom temperature and the gaseous mixture flow, monitored bygaschromatography, is fed in a continuous way, under mechanicalstirring, into a second reactor identical to the one used for the samestep in Example 1. Inside, the temperature is of −70° C. and there are50 g of 1,2-dichloroethylene CClH═CClH and 50 g of CFC1₃.

[0195] At the end of the addition of the reacting gases into the secondreactor, after distillation of the solvent at room pressure, thereaction raw material is distilled by a plate column at the reducedpressure of 100 mmHg. 43.5 g of the mixture of the desired products(isomer C 78%, isomer D 22%, determined by gaschromatography) arecollected. The molar yield of C+D with respect to the used CF₂(OF) ₂ is33%. The isomers have been separated by preparative gaschromatography.

[0196] Characterization of products C and D

[0197] Mixture boiling point (C 78%, D 22%) at the reduced pressure of100 mmHg: 71° C.

[0198]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃=0) of the isomerC perfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane: −56.0/−57.2(2F,O—CF₂—O); −143.2/−146.0(1F, C—CHFCl); −55.8(3F, CF₃—OC); −91.0/−91.4(2F, −90.3/−90.5(2F, C—OC—CF₂OCOC). C—OCF₂—C);

[0199]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃=0) of the isomerD perfluoro-1,2-dichloro-1,2-dihydro-3,5, 7-trioxa-6-methyloctane: −56.0/−57.2(2F, O—CF₂—O); −143.2/−146.0(1F, C—CHFCl);  −54.9/−55.1(3F,CF₃—OC);  −86.2/−86.3(3F, OC(CF₃)O); −100.5/−101.0(1F, OCF(C)O).

[0200]¹H spectrum in p.p.m. (with respect to TMS) of the isomers C andD: 6.28/6.05 (1H -CHFC1); 6.02/5.95 (1H —CHC1—)

[0201] Mass spectrum (electronic impact), main peaks and (respectiveintensities %): 69 (84); 119 (100); 185 (51.1); 251 (84); 281 (15.8);283 (4.8); 347 (5.7); 349 (1.7).

[0202] IR spectrum (cm⁻¹) intensity: (w)=weak, (m)=medium, (s)=strong,(vs)=very strong:

[0203] 3001.0 (w); 2920.9 (w); 2850.9 (w); 1286.3 (vs); 1233.7 (vs);1125.5 (vs); 1081.8 (S); 1047.9 (s); 815.9(m); 766.3 (m)

EXAMPLE 4

[0204] Dehalogenation of perfluoro 1,2-dichloro-3,5-dioxaheptane

[0205] In a 25 ml three-necked flask, equipped with mechanical stirrer,thermometer, dropping funnel, distillation column equipped with waterrefrigerant and collecting trap maintained at −78° C. and connected to amechanical vacuum pump, 150 ml of DMF, 15 g of Zn in powder, 0.5 g ofK₂CO₃ and 100 mg of 1₂ are introduced. The internal temperature isbrought to 80° C. and 50 g of perfluoro -1,2-dichloro-3,5-dioxaheptaneare added drop by drop.

[0206] When the addition is over it is allowed to react for about 30minutes. At the end the internal pressure is gradually brought fromstarting 760 mmHg to 300 mmHg. After about 20 minutes the collectingtrap containing 34.2 g of perfluoro-3,5-dioxa-l-heptene (MOVE 1) isdisconnected.

[0207] The dehalogenation yield is 85%.

[0208] Characterization of perfluoro-3,5-dioxa-l-heptene (MOVE 1)

[0209] Boiling point at atmospheric pressure: 41.9° C.

[0210]¹⁹F-NMR spectrum in p.p.m. with respect to CFC1₃=0:  −56.8(2F,O—CF₂—O);  −87.2(3F, CF₃—C);  −90.6(2F, C—CF₂—O); −114(IF, O—C═C—F);−121.8(1F, O—C═CF); −137(IF, O—C—F═C);

[0211] Mass spectrum (electronic impact) main peaks and respectiveintensities: 69 (66.5%); 119 (100%); 147 (83.4%); 185 (89.4%); 216(67.3%); 282 (8.2%).

[0212] IR spectrum (cm⁻¹) intensity: (w)=weak, (m)=medium, (s)=strong,(vs)=very strong:

[0213] 1839.5 (m); 1407.6 (w); 1307.4 (vs); 1245.8 (VS); 1117.4 (VS)907.2 (m); 846.0 (m)

EXAMPLE 5

[0214] Dehalogenation of the isomer mixture A+B obtained in Example 2perfluoro-1,2-dichloro-3,5,8-trioxanonaneCF₃OCF₂CF₂CF₂OCFClCF₂Cl+perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctaneCF3OCF (CF₃)OCF₂OCFClCF₂Cl).

[0215] In a 250 ml flask equipped as described in the previous Example4, 110 Ml of DMF, 10 g of Zn in powder and 0.3 ml of Br₂ are introduced.The internal temperature is brought to 75° C. and 30.3 g of the binarymixture A+B separated in the previous Example 2 are added drop by drop.When the addition is over the mixture is allowed to ract for about 3hours. At the end the internal pressure is gradually lowered from 760mmHg to 200 mmHg at −79° C. After about 30 minutes the collecting trapis disconnected. The corresponding content, which is washed with water,is recovered. At the end 24.0 g of a mixture formed for 79%(gaschromatographic determination) by perfluoro-3,5,8-trioxa-l-nonene(MOVE 2) CF₃OCF₂CF₂OCF₂OCF═CF₂ (isomer A′) and for 21% byperfluoro-3,5,7-trioxa-6,methyl-1 octene (MOVE 2a)CF₂OCF(CF₃)OCF₂O—CF═CF₂ (isomer B′) are obtained, which are thenseparated by preparative gaschromatography.

[0216] Characterization of products A′ and B′

[0217] Boiling range of the isomer mixture at atmospheric pressure:72.5⁰-74.5° C.

[0218]¹⁹F-NMR spectrum in p.p.m. (with respect to CFC1₃═O) of the isomerA′:

[0219] −55.9 (3F, CF₃—O); −56.9 (2F, O—CF₂—O); −90.8 (2F, C—CF₂—O);−91.2 (2F, O—CF₂—C); —114 (IF, O—C═C—F); —121.8 (IF,—O—C═CF); −137 (IF,O—CF═C)

[0220]¹⁹F-NMR spectrum in p.p.m. (with respect to CFC1₃═O) of the isomerB′:

[0221] −55.9 (3F, CF₃—O); −56.2 (2F, O—CF₂—O); −86.4 (3F, CF₃—C)

[0222] −100.9 (1F, CF; −114 (lF, O—C═C—F); -122 (iF, O—C═CF); -137 (1F,O—CF═C).

[0223] Mass spectrum (electronic impact), main peaks and respectiveintensities of the isomer A′: 69 (74); 81 (18); 119 (100); 147 (59); 185(26); 251 (21);

[0224] Mass spectrum (electronic impact), main peaks and respectiveintensities of the isomer B′: 69 (80); 81 (37); 97 (47); 119 (36); 147(100); 185 (19).

[0225] IR spectrum (cm⁻¹), intensity: (w)=weak, (m)=medium, (s)=strong,(vs)=very strong, 1839 (m); 1343 (s); 1248 (vs); 1145 (vs); 918 (m); 889(m)

EXAMPLE 6

[0226] Dehalogenation of the isomers C+D mixture obtained in Example 3CF₃OCF2CF₂OCF2OCHClCHFClperfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane (isomerC)+CF₃OCF(CF₃) OCF2OCHClCHFClperfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane (isomerD).

[0227] In a 500 ml volume three-necked flask, equipped with mechanicalstirrer, thermometer, dropping funnel, distillation column having awater refrigerant and a collecting trap maintained at the temperature of−78° C., 250 ml of DMF, 30 g of zinc in powder and 300 mg of 2 areintroduced.

[0228] The temperature is brought to 100° C. and 56.9 g of the isomermixture obtained in Example 3 are added drop by drop.

[0229] When the addition is over the reactor internal temperature isbrought to 120° C. and stirring is maintained for 24 hours. At the endthe reaction product, which contains traces of solvent and which iscollected in the trap maintained at −78° C., is distilled. After washingwith water 35 g of a mixture ofperfluoro-1,2-dihydro-3-5-8-trioxa-l-nonene (isomer C′, 79% by moles)and of perfluoro-1,2-dihydro-3-5-7-trioxa-5-methyl-1-octene (isomer D′,21% by moles) are recovered. The isomers are separated by preparativegaschromatography.

[0230] The dehaloagenation reaction yield is 76%.

[0231] Characterization of products C′ and D′

[0232] Boiling range of the mixture of isomers C′ 79%, D′ 21% atatmospheric pressure: 90.0⁰-92.0° C.

[0233]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃═O) of the isomerC, perfluoro-1,2-dihydro-3,5,8-trioxa-l-nonene:  −55.7(3F, CF₃—O);−57.3(2F, O—CF₂—O);  −90.9(2F, C—CF₂—O); −91.2(2F, O—CF₂—C);−149.3/−150.0(1F, O—C═C—F).

[0234]¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃═O) of the isomerD′ perfluoro-1,2-dihydro-3,5,7-trioxa-6-methyl-l-octene:  −55.0(3F,CF₃—O);  −56.9(2F, O—CF₂—O);  −86.2(3F, CF₃—C); −101.0(1F, CF).−149.3/−150.0(1F, O—C═C—F)

[0235] Mass spectrum (electronic impact), main peaks and respectiveintensities): 69 (82); 119 (100); 185 (29); 246 (25); 251 (20); 312(43).

[0236] IR spectrum (cm⁻¹) intensity of the isomer mixture (C′ 79%, D′21%): (w)=weak, (m)=medium, (s)=strong, (vs)=very strong: 3140 (w); 1722(w); 1695 (w); 1402 (m); 1281 (vs); 1237 (vs) 1147 (vs); 1106 (vs); 1030(m)

EXAMPLE 7

[0237] Homopolymerization of perfluoro-3, 5-dioxa-1-heptene (MOVE 1)

[0238] In a glass reactor for polymerizations, having a 20 ml volume,equipped with magnetic stirring and with an inlet for the reactantfeeding and discharge, 60 μl of perfluoropropionylperoxide at 3% byweight in CFC1₂CF₂Cl and 3 g of MOVE 1 are in sequence introduced. Theso charged reactor is brought to the temperature of −196° C., evacuated,brought to room temperature, the all twice. At the end of the degassingoperations the reactor is thermostated at the temperature of 30° C. andit is allowed to react under these conditions for two days undermagnetic stirring.

[0239] The reaction raw material which is finally recovered appears as aslightly viscous, transparent, colourless and homogeneous solution.

[0240] After distillation of the unreacted monomer, and subsequentstripping under vacuum at 150° C. for 3 hours, 180 mg of the polymer areseparated.

[0241] The IR analysis of the obtained polymer shows that, in thespectrum absorption bands in the zone of the fluorinated double bondsare absent.

[0242] The ¹⁹F-NMR analysis carried out on the polymer dissolved in C₆F₆is in accordance with the homopolymer structure having a molecularweight of 50,000. The analysis does not show the presence of unreactedmonomer.

[0243] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The polymer T_(g) determined by DSC,is −35.4° C. The thermogravimetric analysis (TGA) shows a weight loss of2% at 332° C. and of 10% at 383° C.

EXAMPLE 8

[0244] Copolymer between perfluoro-3,5,8-trioxa-l-noneneCF₃OCF₂CF₂OCF₂OCF═CF₂ (MOVE ₂) and perfluoro-3,5,7-trioxa-6,methyl-1-octene CF₃OCF(CF₃)OCF₂O—CF═CF₂ (MOVE 2a).

[0245] In a reactor having the same characteristics as that described inExample 7, 150 μl of perfluoropropionyl-peroxide at 3% by weight inCFCl₂CF₂Cl and 3.2 g of a mixture prepared according to the process ofExample 5 and containing 83% MOVE 2 and 17% MOVE 2a, are introduced. Thereactor is then evacuated, cooled, and the subsequent reaction carriedout as described in the previous Example 7.

[0246] The reaction raw material appears as a slightly viscous,transparent, colourless and homogeneous solution. The monomers whichhave not reacted are distilled and a stripping under vacuum at 150° C.for 3 hours is in sequence carried out. Finally 350 mg of the polymerare separated.

[0247] The IR analysis shows that in the polymer spectrum, absorptionbands in the zone of the fluorinated double bonds are absent.

[0248] The ¹⁹F-NMR analysis is in accordance with the copolymerstructure having an average molecular weight of 35,000 and a MOVE 2/MOVE2a content equal to the percentages of the reacting mixture; unreactedmonomers are not evident.

[0249] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The polymer Tg, determined by DSC,is −52.6° C. The thermogravimetric analysis (TGA) shows a weight loss of2% at 280° C. and of 10% at 327° C.

EXAMPLE 9

[0250] Amorphous copolymer between MOVE 1 and TFE.

[0251] In an AISI-316 polymerization reactor having a 40 ml volume,equipped with magnetic stirring, pressure transducer and an inlet forthe reactant feeding and discharge, 250 μl of perfluoropropionylperoxideat 3% by weight in CFC1₂CF₂Cl, 9.8 mmoles of MOVE 1 and 18 mmoles oftetrafluoroethylene are introduced.

[0252] The reactor is cooled to the temperature of −196° C., evacuated,then brought to room temperature and cooled again, the all twice.

[0253] At the end of the degassing operations the reactor isthermostated at the temperature of 30° C. and the reaction mixturemaintained under magnetic stirring. The internal pressure decreases from6.4 atm to 4.7 atm in about 8 hours (reaction time).

[0254] After distillation of the unreacted monomers, and polymerstripping under vacuum for 3 hours at 150° C., 1,100 mg of polymer arerecovered, which appears as a transparent and colourless rubber.

[0255] By ¹⁹F-NMR analysis of the polymer dissolved under heating inC₆F₆ it is determined that the MOVE 1 molar percentage in the polymer is24%.

[0256] The IR analysis does not show in the polymer spectrum absorptionbands in the zone of the fluorinated double bonds, and shows thepresence of very small absorption bands in the zone of the carboxylsignals. The intensity of these signals, compared with the similar onesobtained from a film having the same thickness obtained with the polymerof the comparative Example 1, is equal to about {fraction (1/10)} ofthese latter.

[0257] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC is−21.4° C.

[0258] The TGA shows a weight loss of 2% at 450° C. and of 10% at 477°C. The polymer therefore results thermally more stable with respect tothe comparative Example (see afterwards).

[0259] The polymer intrinsic viscosity measured at 30° C. in Fluorinert®FC-75, is 35.5 ml/g.

EXAMPLE 10

[0260] Amorphous co-polymer between MOVE 1 and TFE.

[0261] In an AISI-316 polymerization reactor identical to that describedin the previous Example 9, 250 μl of perfluoropropionylperoxide at 3% byweight in CFC1₂CF₂Cl, 9.75 mmoles of MOVE 1 and 9 mmoles oftetrafluoroethylene are in sequence introduced.

[0262] The procedure already described in the previous Example 9 is thenfollowed until the thermostating step at the temperature of 30° C. undermagnetic stirring. During the reaction the internal pressure decreasesfrom 3.4 atm to 2.9 atm in about 8 hours.

[0263] At the end the unreacted monomers are distilled and the polymeris stripped under vacuum at 150° C. for 3 hours.

[0264] 480 mg of the polymer are separated.

[0265] By ¹⁹F-NMR analysis of the polymer dissolved under heating inC₆F₆ it is determined that the MOVE 1 molar percentage in the polymer is39%.

[0266] The IR analysis shows that in the polymer spectrum absorptionbands in the zone of the fluorinated double bonds are absent.

[0267] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC is−29.8° C.

[0268] The TGA shows a weight loss of 10% at 435° C.

EXAMPLE 11

[0269] Amorphous copolymer between MOVE 1 and CF₂═CH₂

[0270] In a polymerization reactor identical to that described inExample 9, 250 μl of perfluoropropionylperoxide at 3% by weight inCFC1₂CF₂Cl 10 mmoles of MOVE 1 and 18 mmoles of VDF are in sequenceintroduced.

[0271] The procedure already described in the previous Example 9 isfollowed until the thermostating step at the temperature of 30° C. undermagnetic stirring. The internal pressure decreases from 6.8 atm to 5.0atm during the reaction (about 8 hours).

[0272] After distillation of the unreacted monomers, and subsequentpolymer stripping under vacuum at 1500C for 3 hours, 1,600 mg of thepolymer are separated, appearing as a transparent and colourless rubber.

[0273] By the ¹⁹F-NMR analysis carried out on the polymer dissolved inC₆F₆ it is determined that the MOVE 1 molar percentage in the polymer is40%.

[0274] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC, is −47°C.

[0275] The TGA shows a weight loss of 2% at 428° C. and of 10% at 455°C.

EXAMPLE 12

[0276] Amorphous terpolymer MOVE 2/MOVE 2a/TFE.

[0277] In a polymerization reactor identical to that described inExample 9, 100 μl of perfluoropropionyl-peroxide at 6% by weight inCFC1₂CF₂Cl, 10 mmoles of a MOVE 2 83% and MOVE 2a 17% mixturesinthetized according to the process of Example 5, and 18 mmoles oftetrafluoroethylene (TFE) are in sequence introduced.

[0278] The procedure already described in the previous Example 9 is thenfollowed until thermostating at the temperature of 30° C. under magneticstirring. The internal pressure decreases from 6.1 atm to 3.9 atm duringthe reaction (about 8 hours).

[0279] After distillation of the unreacted monomers and polymerstripping under vacuum at 150° C. for 3 hours, the polymer is separated.

[0280] By the ¹⁹F-NMR analysis carried out on the polymer dissolved inC₆F₆ it results that the total molar percentage of the MOVE 2+MOVE 2aperfluorovinyl ethers in the polymer is 22%; the MOVE 2/MOVE 2a ratio bymoles in the polymer is 83/17 and it is equal to that of the startingfed mixture.

[0281] The presence of unreacted monomers is not evident.

[0282] The IR analysis does not show in the polymer spectrum absorptionbands in the zone of the fluorinated double bonds, and it shows thepresence of very small absorptions in the zone of the carboxyl signals.The intensity of these signals, compared with the similar ones obtainedfrom a film having the same thickness obtained with the polymer of thecomparative Example 1, is equal to about {fraction (1/10)} of thelatter.

[0283] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The Tg determined by DSC, is −37.5°C.

[0284] The TGA shows a weight loss of 10% at 473° C.

[0285] The polymer intrinsic viscosity measured at 30° C. in Fluorinert®FC-75, is 40.0 ml/g.

EXAMPLE 13

[0286] Amorphous terpolymer MOVE 2/MOVE 2a/TFE.

[0287] In a polymerization reactor identical to that described inExample 9, 100 μl of perfluoropropionylperoxide at 6% by weight in CFC1₂CF₂Cl, 9.7 mmoles of the MOVE 2 (83%) and MOVE 2a (17%) mixturesinthetized according to the process of Example 5, and 10 mmoles oftetrafluoroethylene (TFE) are in sequence introduced.

[0288] The procedure already described in the previous Example 9 is thenfollowed until the thermostating step at the temperature of 30° C. undermagnetic stirring. The internal pressure decreases from 3.6 atm to 2.7atm during the reaction course (about 8 hours).

[0289] After distillation of the unreacted monomers and polymerstripping under vacuum at 150° C. for 3 hours 652 mg of polymer areseparated.

[0290] By the ¹⁹F-NMR analysis carried out on the polymer dissolved inC₆F₆ it results that the total molar percentage of the MOVE 2+MOVE 2aperfluorovinyl ethers in the polymer is 37%; the MOVE 2/MOVE 2a molarratio in the polymer is 83/17 and it is equal to that of the startingfed mixture.

[0291] The presence of unreacted monomers is not evident.

[0292] The IR analysis does not show in the polymer spectrum absorptionbands in the zone of the fluorinated double bonds.

[0293] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC, is−44.5° C.

[0294] The TGA shows a weight loss of 10% at 451° C.

[0295] The polymer intrinsic viscosity measured at 30° C. in Fluorinert®FC-75, is 16.7 ml/g.

EXAMPLE 14

[0296] Amorphous copolymer betweenperfluoro-1,2-dihydro-3,5,8-trioxa-l-nonene (H-MOVE 2) andperfluoro-1,2-dihydro-3,5, 7-trioxa-6-methyl-l-octene (H-MOVE 2a) withmolar ratio 88/12.

[0297] In a reactor identical to that described in Example 7, 200 μl ofperfluoropropionylperoxide at 3% by weight in CFCl₂—CF₂Cl and 3.1 g of aH-MOVE 2/H-MOVE 2a 88/12 mixture are introduced.

[0298] The procedure described in Example 7 is followed.

[0299] The recovered reaction raw material appears as a slightlyviscous, transparent, colourless and homogeneous solution.

[0300] After distillation of the unreacted monomer and subsequentstripping under vacuum at 150° C. for 3 hours, 120 mg of polymer areseparated.

[0301] The IR analysis of the obtained polymer shows that in the polymerspectrum absorption bands in the zone of the fluorinated double bondsare absent.

[0302] The ¹⁹F-NMR analysis is in accordance with the copolymerstructure having a content of monomers H-MOVE 2 and H-MOVE 2a equal tothe H-MOVE 2 and H-MOVE 2a percentages in the reacting mixture. Theanalysis does not show the presence of unreacted monomers. The DSC graphdoes not show any melting endothermic curve, wherefore the polymer isamorphous. The polymer T_(g). determined by DSC, is —58.0° C. Thethermogravimetric analysis (TGA) shows a weight loss of 10% at 307° C.

EXAMPLE 15

[0303] Terpolymer H-MOVE 2/H-MOVE 2a/TFE.

[0304] In a reactor similar to that described in Example 9, 100 μl ofperfluoropropionylperoxide at 6% by weight of CFCl₂—CF₂Cl and 5 mmolesof a H-MOVE 2 (88%) and H-MOVE 2a (12%) mixture and 18 mmoles oftetrafluoroethylene, are introduced.

[0305] The same procedure described in Example 9 is followed.

[0306] At the end of the degassing, the reactor is thermostated at thetemperature of 30° C. under magnetic stirring. The internal pressuredecreases from 6.8 atm to 6.5 atm in about 6 hours (reaction time).

[0307] After distillation of the unreacted monomers, and polymerstripping under vacuum at 150° C. for 3 hours, 300 mg of the polymer areseparated.

[0308] By ¹⁹F-NMR analysis of the polymer dissolved under heating inC₆F₆ it is calculated that the molar percentage of the perfluorovinylethers (H-MOVE 2+H-MOVE 2a) contained in the polymer is 33%. The H-MOVE2/H-MOVE 2a molar ratio in the polymer is equal to the H-MOVE 2/H-MOVE2a molar ratio of the fed mixture. Unreacted monomers are not evident.

[0309] The IR analysis does not show in the polymer spectrum absorptionbands in the zone of the fldorinated double bonds.

[0310] The DSC graph does not show any melting endothermic curvewherefore the polymer is amorphous. The Tg determined by DSC, is −44.5°C.

[0311] The TGA shows a weight loss of 10% at 450° C.

EXAMPLE 1 (comparative)

[0312] Copolymer PVE/TFE.

[0313] In a polymerization reactor identical to that described inExample 9, 250 μl of perfluoropropionylperoxide at 3% by weight inCFCl₂CF₂Cl, 9.8 mmoles of PVE and 18 mmoles of tetrafluoroethylene, arein sequence introduced.

[0314] The procedure already described in the previous Example 9 isfollowed until thermostating at the temperature of 30° C. under magneticstirring. The reaction time is of eight hours.

[0315] After distillation of the unreacted monomers and stripping undervacuum at 150° C. for 3 hours, 540 mg of polymer are recovered.

[0316] By the ¹⁹F-NMR analysis carried out on the polymer dissolved inC₆F₆ it is calculated that the PVE molar percentage in the polymer is23%.

[0317] The IR analysis shows that in the polymer spectrum there areabsorption bands in the carboxyl zone, whose intensity is 10 timeshigher than that obtained from a MOVE 1/TFE copolymer film preparedaccording to Example 9, and having the same thickness:

[0318] The DSC graph does not show any melting endothermic curve,wherefore the polymer is amorphous. The TGA shows a weight loss of 2% at427° C. and of 10% at 463° C. The Tg, determined by DSC, is +15° C.

[0319] The polymer intrinsic viscosity, measured at 30° C. inFluorinert® FC-75, is 51 ml/g.

EXAMPLE 2 (comparative)

[0320] Copolymer between β-PDE (CF₃OCF₂CF₂OCF═CF₂)/TFE.

[0321] In a polymerization reactor identical to that described inExample 9, 250 μl of perfluoropropionylperoxide at 3% by weight inCFCl₂—CF₂Cl 10 mmoles of β-PDE and 18 mmoles of tetrafluoroethylene, arein sequence introduced.

[0322] The procedure described in the previous Example 9 is followeduntil the thermostating step at the temperature of 30° C. under magneticstirring.

[0323] By the ¹⁹F-NMR analysis carried out on the polymer purified fromthe monomers by the processes described in the previous Examples, it iscalculated that the molar percentage of β-PDE in the polymer is 23%.

[0324] The DSC graph does not show any melting endothermic curvewherefore the polymer is amorphous. The T_(g), determined by DSC, is−4.8° C. This Tg value is clearly higher than those obtainable with thevinyl ethers of the invention (see above).

I claim
 1. A fluoroelastomer comprising units derived from fluorovinylethers of formula: CFX═CXOCF₂OR  (I) wherein: 1) R is a C₂-C₆ linear orbranched perfluoroalkyl group, a C₅-C₆ cyclic perfluoroalkyl group, or alinear or branched perfluorooxyalkyl group comprising 2 to 6 carbonatoms and 1 to 3 oxygen atoms; 2) up to two fluorine atoms of theperfluoroalkyl group or the perfluorooxyalkyl group can be independentlyreplaced with atoms selected from the group consisting of H, Cl, Br, andI; and 3) X is F or H.
 2. The fluoroelastomer of claim 1 wherein R isCF₂CF₂Y and Y is F or OCF₃.
 3. The fluoroelastomer of claim 2 whereineach X is F.
 4. The fluoroelastomer of claim 3 wherein Y is F.
 5. Thefluoroelastomer of claim 1 further comprising in the polymer chain unitsderived from either: 1) vinylidene fluoride and at least one additionalcopolymerizable comonomer selected from a C₂-C₈ perfluoroolefin; a C₂-C₈chlorofluoroolefin; a C₂-C₈ bromofluoroolefin; a C₂-C₈ iodofluoroolefin;a fluoroalkyl vinyl ether of structure CF₂═CFOR^(t) _(f), wherein R^(t)_(f) is a C₁-C₆ alkyl group in which from one up to all hydrogen atomsare replaced with fluorine atoms; a perfluorooxyalkyl vinyl ether ofstructure CF₂═CFOX^(t), wherein x^(t) is a C₁-C₁₂ perfluorooxyalkylgroup having one or more ether oxygens; or a C₂-C₈ olefin; or 2)tetrafluoroethylene and at least one additional copolymerizablecomonomer selected from; fluoroalkyl vinyl ethers of structureCF₂═CFOR^(t) _(f), wherein R^(t) _(f) is as above defined;perfluorooxyalkyl vinyl ethers of structure CF₂═CFOX^(t), wherein x^(t)is as above defined; C₂-C₈ fluoroolefin, chlorofluoroolefins,bromofluoroolefins, and iodofluoroolefins; and C₂-C₈ olefins.
 6. Thefluoroelastomer of claim 5 wherein the C₂-C₈ perfluoroolefin is eithertetrafluoroethylene, hexafluoropropene, or hexafluoroisobutene.
 7. Thefluoroelastomer of claim 5 wherein the C₂-C₈ chlorofluoroolefin ischlorotrifluoroethylene.
 8. The fluoroelastomer of claim 5 wherein theC₂-C₈ bromofluoroolefin is bromotrifluoroethylene.
 9. Thefluoroelastomer of claim 5 wherein the fluoroalkyl vinyl ether isheptafluoropropyl trifluorovinyl ether.
 10. The fluoroelastomer of claim5 wherein the perfluorooxyalkyl vinyl ether istetradecylfluoro-2-propoxypropyl trifluorovinyl ether.
 11. Thefluoroelastomer of claim 5 wherein the C₂-C₈ olefin is either ethyleneor propylene.
 12. A fluoroelastomer made by the copolymerization of oneor more comonomers, which comonomers together comprise a basefluoroelastomer composition, with a fluorovinyl ether of formula:CFX═CXOCF₂OR  (I) wherein 1) R is a C₂-C₆ linear or branchedperfluoroalkyl group, a C₅-C₆ cyclic perfluoroalkyl group, or a linearor branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1to 3 oxygen atoms; 2) up to two fluorine atoms of the linear, branchedor cyclic perfluoroalkyl group or the perfluorooxyalkyl group can beindependently replaced with an atom selected from the group consistingof H, Cl, Br, and I; and 3) X is F or H; wherein a sufficient amount offluorovinyl ether is used in the copolymerization to result in anelastomeric copolymer.
 13. The fluoroelastomer of claim 12 wherein R isCF₂CF₂Y and Y is F or OCF₃.
 14. The fluoroelastomer of claim 13 whereineach X is F.
 15. The fluoroelastomer of claim 14 wherein Y is F.
 16. Thefluoroelastomer of claim 12 wherein the amount of fluorovinyl ether usedin the copolymerization is at least about 10 mole %, the remaindercomprising one or more comonomers.
 17. The fluoroelastomer of claim 16wherein the amount of fluorovinyl ether used is at least about 15 mole%.
 18. The fluoroelastomer of claim 17 wherein the amount of fluorovinylether used is between about 15 mole % and about 20 mole %.
 19. Thefluoroelastomer of claim 12 wherein the one or more comonomers arefluorinated compounds having at least one polymerizable carbon-carbondouble bond, said comonomers being capable of forming copolymers withthe fluorovinyl ether.
 20. The fluoroelastomer of claim 19 wherein thefluorinated compound further comprises at least one atom selected fromthe group consisting of chlorine, bromine, iodine, and oxygen.
 21. Thefluoroelastomer of claim 19 , wherein the olefin is copolymerized withat least one comonomer that is a C₂-C₈ olefin.
 22. The fluoroelastomerof claim 21 wherein the olefinically unsaturated hydrocarbon is selectedfrom the group consisting of ethylene, propylene, and isobutylene. 23.The fluoroelastomer of claim 19 wherein the one or more comonomers areselected from the following: 1) C₂-C₈ perfluoroolefins; 2) C₂-C₈fluoroolefins; 3) C₂-C₈ chlorofluoroolefins, 4) C₂-C₈bromofluoroolefins, 5) C₂-C₈ iodofluoroolefins; 6) perfluoroalkyl vinylethers having the structure CF₂=CFOR f (PAVE), wherein R f is a Cl-C₆perfluoroalkyl group in which 0 or 1 of the fluorine atoms is replacedwith a bromine atom; 7) fluorooxyalkyl vinyl ethers having the structureCF₂═CFOX^(a), wherein X^(a) is a C₁-C₁₂ alkyl group, a C₁-C₁₂ oxyalkylgroup, or a C₁-C₁₂ perfluorooxyalkyl group having at least one etheroxygen; 8) sulphonic monomers having the structure CF₂═CFOX^(b)SO₂F,wherein X^(b) is selected from CF₂CF₂, CF₂CF₂CF₂, and CF₂CF(CFX^(C)),and wherein X^(c) is selected from F, Cl, and Br; 9) a bis-olefin havingthe general formula R^(I) ₁R^(I) ₂C═CR^(I) ₃,—Z—CR^(I) ₄═CR^(I) ₅R^(I)₆  (IA) wherein; R^(I) ₁, R^(I) ₂, R^(I) ₃, R^(I) ₄, R^(I) ₅, and R^(I)₆, are the same or different and are either H or C₁-C₅ alkyl; and Z is aC₁-C₁₈ linear or branched alkylene or cycloalkylene diradical in whichnone to all of the hydrogen atoms are replaced with fluorine, or Z is apolyoxyalkylene diradical in which none to all of the hydrogen atoms arereplaced with fluorine.
 24. The fluoroelastomer of claim 23 wherein theperfluoroolefin is selected from the group consisting oftetrafluoroethylene (TFE), hexafluoropropene (HFP), andhexafluoroisobutene.
 25. The fluoroelastomer of claim 23 wherein thefluoroolefin is selected from the group consisting of vinylfluoride(VF), vinylidene fluoride (VDF), trifluoroethylene, and fluoroalkenesrepresented by the formula CH₂═CHR² _(f), wherein R² _(f) is a linear orbranched C₁-C₆ perfluoroalkyl group.
 26. The fluoroelastomer of claim 23wherein the comonomer is either chlorotrifluoroethylene orbromotrifluoroethylene.
 27. The fluoroelastomer of claim 23 whereinX^(a) is the tetradecafluoro-2-propoxypropyl group.
 28. Thefluoroelastomer of claim 23 wherein Z is at least partially fluorinated.29. The fluoroelastomer of claim 23 wherein Z is aperfluoropolyoxyalkylene diradical.
 30. The fluoroelastomer of claim 23wherein Z is a C₄-C₁₂ perfluoroalkylene diradical and R^(I) ₁, R^(I) ₂,R^(I) ₃, R^(I) ₄, R^(I) ₅, R^(I) ₆ are H.
 31. The fluoroelastomer ofclaim 23 wherein Z is a fluoropolyoxyalkylene diradical having theformula: —(Q)_(p)—CF₂O—(CF₂CF₂O)_(ma)(CF₂O)_(na)—CF₂—(Q)_(p)—  (IIA)wherein: a) Q is a C₁-C₁₀ alkylene or oxyalkylene radical; b) p is 0 or1; c) ma and na are integers such that the ma/na ratio is between about0.2 and about 5; and d) the molecular weight of thefluoropolyoxyalkylene diradical is between about 500 and about 10,000.32. The fluoroelastomer of claim 31 wherein the molecular weight of thefluoropolyoxyalkylene diradical is between about 1,000 and about 4,000.33. The fluoroelastomer of claim 31 wherein Q is selected from —CH₂OCH₂—and —CH₂O(CH₂CH₂O)_(s)CH₂— wherein s is 1 to
 3. 34. The fluoroelastomerof claim 23 wherein the amount of bis-olefin of formula (IA) used incopolymerization is such that between about 0.001 and about 1 molepercent of repeat units in the polymer are dervied from the bis-olefin.35. The fluoroelastomer of claim 12 wherein the base fluoroelastomercomposition is comprised of one or more comonomers selected from: 1)vinylidene fluoride and at least one additional comonomer selected froma C₂-C₈ perfluoroolefin; a C₂-C₈ chlorofluoroolefin; a C₂-C₈bromofluoroolefin; a C₂-C₈ iodofluoroolefin; a fluoroalkyl vinyl etherof structure CF₂═CFOR^(t) _(f), wherein R^(t) _(f) is a C₁-C₆ alkylgroup in which from one up to all hydrogen atoms replaced with fluorineand up to one such hydrogen atom not replaced with fluorine is replacedwith bromine; perfluorooxyalkyl vinyl ethers of structure CF₂═CFOX^(t),wherein x^(t) is a C₁-C₁₂ perfluorooxyalkyl group having one or moreether oxygens; and a C₂-C₈ olefin; or 2) tetrafluoroethylene and atleast one additional comonomer selected from a perfluoroalkylvinyletherof structure CF₂═CFOR^(t) _(f), wherein R^(t) _(f) is as above defined;perfluorooxyalkylvinyl ethers of structure CF₂═CFOX^(t), wherein x^(t)is as above defined; a C₂-C₈ fluoroolefin, a C₂-C₈ chlorofluoroolefin, aC₂-C₈ bromofluoroolefins, or a C₂-C₈ iodofluoroolefin; and a C₂-C₈olefin.
 36. The fluoroelastomer of claim 35 wherein the C₂-C₈perfluoroolefin is selected from tetrafluoroethylene andhexafluoropropylene.
 37. The fluoroelastomer of claim 35 wherein theC₂-C₈ chlorofluoroolefin is chlorotrifluoroethylene.
 38. Thefluoroelastomer of claim 35 wherein the C₂-C₈ bromofluoroolefin isbromotrifluoroethylene.
 39. The fluoroelastomer of claim 35 wherein thefluoroalkyl vinyl ether is pentafluoropropyl trifluorovinyl ether. 40.The fluoroelastomer of claim 35 wherein the perfluorooxyalkyl vinylether is perfluoro-2-propoxypropyl vinyl ether.
 41. The fluoroelastomerof claim 35 wherein the C₂-C₈ olefin is either ethylene or propylene.42. A fluoroelastomer, curable by a peroxidic route, comprising unitsderived from the following monomers: 1) from about 45 mole % to about 65mole % vinylidene fluoride; 2) from 0 to about 45 mole % of eitherhexafluoropropene or a perfluoroalkyl vinyl ether of structure CF₂═CFOR²_(f), wherein R²f is a C₁-C₆ perfluoroalkyl group in which 0 or 1fluorine atoms are replaced with bromine atoms; 3) from 0 to about 30mole % tetrafluoroethylene; 4) from 0 to about 40 mole % of a C₂-C₈olefin; and 5) from 5 to about 40 mole % of a fluorovinyl ether offormula CFX═CXOCF₂OR  (I) wherein: a) R is a C₂-C₆ linear or branchedperfluoroalkyl group, a C₅-C₆ cyclic perfluoroalkyl group, or a linearor branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1to 3 oxygen atoms; b) up to two fluorine atoms of the perfluoroalkylgroup or the perfluorooxyalkyl group can be independently replaced withan atom selected from the group consisting of H, Cl, Br, and I; and c) Xis F or H; with the proviso that, together, less than about 45 mole % ofall units in the fluoroelastomer are dervived from hexafluoropropene,perfluoroalky vinyl ether, and perfluorovinyl ether combined.
 43. Thefluoroelastomer of claim 42 having one or more atoms selected frombromine and iodine.
 44. The fluoroelastomer of claim 42 in the form ofan O-ring.
 45. A fluoroelastomer, curable by a peroxidic route,comprising units derived from the following monomers: 1) from about 50mole % to about 85 mole % tetrafluoroethylene; 2) from 0 to about 50mole % of a perfluoroalkyl vinyl ether of structure CF₂═CFOR² _(f),wherein R² _(f) is a C₁-C₆ perfluoroalkyl group in which 0 or 1 fluorineatoms are replaced with bromine atoms; 4) from 0 to about 40 mole % of aC₂-C₈ olefin; and 5) from about 1 to about 40 mole % of a fluorovinylether of formula CFX═CXOCF₂OR wherein: a) R is a C₂-C₆ linear orbranched perfluoroalkyl group, a C₅-C₆ cyclic perfluoroalkyl group, or alinear or branched perfluorooxyalkyl group comprising 2 to 6 carbonatoms and 1 to 3 oxygen atoms; b) up to two fluorine atoms of theperfluoroalkyl group or the perfluorooxyalkyl group can be independentlyreplaced with an atom selected from the group consisting of H, Cl, Br,and I; and c) X is F or H; with the proviso that, together, less thanabout 50 mole % of the units are derived from perfluoroalky vinyl etherand fluorovinyl ether.
 46. The fluoroelastomer of claim 45 having one ormore atoms that selected from bromine and iodine.
 47. Thefluoroelastomer of claim 45 in the form of an 0-ring.
 48. Afluoroelastomer, curable by an ionic route, comprising units derivedfrom the following monomers in the given amounts: 1) between about 48mole % and about 85 mole % vinylidene fluoride; 2) from 20 mole % up toabout 35 mole % hexafluoropropene; 3) from 0 up to about 6 mole % of aperfluoroalkyl vinyl ether of structure CF₂=CFOR² _(f), wherein R²f is aC₁-C₆ perfluoroalkyl group in which 0 or 1 fluorine atoms are replacedwith bromine atoms; 3) from 0 up to about 20 mole % tetrafluoroethylene;4) from about 3 mole % to about 9 mole % of a fluorovinyl ether offormula CFX═CXOCF₂OR wherein: a) R is a C₂-C₆ linear or branchedperfluoroalkyl group, a C₅-C₆ cyclic perfluoroalkyl group, or a linearor branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1to 3 oxygen atoms; b) up to two fluorine atoms of the perfluoroalkylgroup or the perfluorooxyalkyl group can be independently replaced withan atom selected from the group consisting of H, Cl, Br, and I; and c) Xis F or H; with the proviso that, together, less than about 10 mole % ofthe units are derived from perfluoroalkyl vinyl ether andperfluoorovinyl ether combined.
 49. The fluoroelastomer of claim 48 inthe form of an O-ring.
 50. A fluoroelastomer, curable by an ionic route,comprising units derived from the following monomers: 1) from about 30mole % to about 47 mole % vinylidene fluoride; 2) from about 20 mole %to about 40 mole % hexafluoropropene; 3) from 0 up to about 17 mole % ofa perfluoroalkyl vinyl ether of structure CF₂═CFOR² _(f), wherein R²f isa C₁-C₆ perfluoroalkyl group in which 0 or 1 fluorine atoms are replacedwith bromine atoms; 4) from about 10 mole % to about 30 mole %tetrafluoroethylene; and 5) from about 3 mole % to about 20 mole % of afluorovinyl ether of formula CFX═CXOCF₂OR wherein: 1) R is a C₂-C₆linear or branched perfluoroalkyl group, a C₅-C₆ cyclic perfluoroalkylgroup, or a linear or branched perfluorooxyalkyl group comprising 2 to 6carbon atoms and 1 to 3 oxygen atoms; 2) up to two fluorine atoms of theperfluoroalkyl group or the perfluorooxyalkyl group can be independentlyreplaced with an atom selected from the group consisting of H, Cl, Br,and I; and 3) X is F or H; with the proviso that, together, less thanabout 20 mole % of the units are derived from perfluoroalkyl vinyl etherand perfluorovinyl ether combined.
 51. The fluoroelastomer of claim 50in the form of a hose.